User Philip has posted a forumpost on msx.org on how to upgrade a NMS8245 to a MSX2plus. This blogpost will describe this upgrade step by step supported with pictures and the necessary ROM files to do this upgrade your self.

(thank you Philip for making this post possible)

Since I’m upgrading a NMS8245 that already has a memory upgrade, this first image is for reference only. For this upgrade I’m using blue solid wire (please ignore all other colored wires)

Step 1 : Remove the mainboard from the NMS8245

Step 2 : Remove the V9938 by cutting all pins and then desolder the pins from the mainboard. Also remove the heatsink by cutting it directly above the mainboard. You can re-use it for the new VDP.

Step 3 : Place an IC socket on the empty space, where the V9938 is removed. Notice that the little notch in the socket is aligned with the notch printed on the mainboard. Don’t solder the new V9958 directly on the mainboard.

Step 4 : On the V9958 these pins have to be bend so they are not inserted into the socket: 4 (vreset) 21 (vdd) 26 (wait) 27 (hreset) Place the V9958 in the socket with Pin1 (the little dot on the V9958) on the side of the notch.